Thane society switches to solar power, will cut electricity bills by Rs8 lakh a year

The society paid a subsidised rate of Rs20 lakh for the solar system

Members of Hill Crest Society in Thane display their solar panels on Monday.(Praful Gangurde)

Thane’s Hill Crest Society is expected to save Rs8 lakh in electricity bills every year. How? On Sunday, it adopted a net metering system, in which solar panels installed on the terrace generate enough energy to power the complex’s lifts, water pumps and lights.

Net metering enables a building to generate renewable energy equal to the power it consumes, thus reducing its dependence on electricity. Excess power generated can be added to the power company’s grid, resulting in a reduction in tenants’ bills.

“We have installed solar panels on our terrace. The energy they generate will reduce our monthly bills by Rs65,000 and annual bill by Rs8 lakh,” said Sushma Goregaonkar, chairman of the six-building society set up 20 years ago.

“We got a government subsidy of 30%. The net metering technology came with a 25-year warranty for the solar panels and a five-year warranty for the solar inverters. We are thus not anticipating any major expenses for the next five years. Getting the solar panels cleaned once a week is our only recurring expense. According to our calculations, we have paid an amount equal to our electricity bill for two-and-a-half years and are getting free electricity for a lifetime,” Goregaonkar said.

Two years ago, the Thane Municipal Corporation (TMC) converted the Vartak Nagar ward office into a zero-power consumption building, following which the concept of net metering became popular with other establishments.

“Around 18 societies in Thane have adopted net metering and are collectively generating more than 1 mega watt power daily. In the past, solar panels required expensive batteries, which deterred residents from opting for them. However, with net metering, batteries are not required, which decreases the cost by an additional 30%,” said Sunil Pote, deputy city engineer, electrical department.

What is net metering?

Net metering is the adjustment in billing by electricity providers, in exchange for renewable energy supplied to the grid. There are three potential situations:

If the solar panels generate electricity equivalent to the building’s requirement, the electricity bill will be zero.

If surplus electricity is generated, then the company will pay the difference to the consumer, in exchange for this surplus power.

In case the building requires more energy than it can generate, the company will deduct the units generated through solar energy and bill the tenants only for the electricity used from the grid.

How does a zero-net corporation work?

The Thane Municipal Corporation currently consumes 28 to 30 megawatt electricity across all its properties. The net-zero corporation project aims at reducing consumption to zero by generating electricity through alternative sources. The corporation has implemented net-zero metering in some of its civic schools. Solar panels installed at these schools generate around 267 kilowatt energy a day. Additionally, 10 megawatt is generated daily through solar panels installed at various TMC properties such as theatres, ward offices, hospitals and bus stops.